Nerve Atlas

Comprehensive reference of origins, courses, distributions, and functions of major nerves

Cranial Nerves

Nerve Origin Course Distribution Function
Olfactory (CN I) Olfactory epithelium Through cribriform plate to olfactory bulb Olfactory epithelium in nasal cavity Sensory - smell
Optic (CN II) Retinal ganglion cells Through optic canal to optic chiasm and tract Retina Sensory - vision
Oculomotor (CN III) Midbrain Through superior orbital fissure Superior, medial, inferior rectus, inferior oblique, levator palpebrae superioris muscles; ciliary body, iris Motor - eye movement, pupillary constriction, accommodation; parasympathetic to intrinsic eye muscles
Trochlear (CN IV) Midbrain Through superior orbital fissure Superior oblique muscle Motor - eye movement (downward and laterally when eye is adducted)
Trigeminal (CN V) Pons Three divisions exit through different foramina Face, anterior scalp, oral and nasal cavities, meninges Mixed - sensory to face, motor to muscles of mastication
Abducens (CN VI) Pons Through superior orbital fissure Lateral rectus muscle Motor - lateral eye movement
Facial (CN VII) Pons Through internal acoustic meatus, facial canal, stylomastoid foramen Facial expression muscles, submandibular and sublingual glands, anterior 2/3 of tongue, lacrimal gland Mixed - motor to facial muscles, parasympathetic to glands, sensory taste (anterior 2/3 of tongue)
Vestibulocochlear (CN VIII) Inner ear Through internal acoustic meatus Cochlea and vestibular apparatus Sensory - hearing and balance
Glossopharyngeal (CN IX) Medulla Through jugular foramen Pharyngeal muscles, parotid gland, posterior 1/3 of tongue, carotid body and sinus Mixed - motor to pharynx, parasympathetic to parotid, sensory taste (posterior 1/3 of tongue), carotid monitoring
Vagus (CN X) Medulla Through jugular foramen Pharynx, larynx, thoracic and abdominal viscera Mixed - motor to pharynx and larynx, parasympathetic to viscera, sensory from viscera
Accessory (CN XI) Medulla and upper cervical spinal cord Through jugular foramen Sternocleidomastoid and trapezius muscles Motor - neck and shoulder movement
Hypoglossal (CN XII) Medulla Through hypoglossal canal Intrinsic and extrinsic muscles of tongue Motor - tongue movement

Cervical Plexus (C1-C4)

Nerve Origin Course Distribution Function
Greater auricular C2-C3 Wraps around sternocleidomastoid to ear Skin of ear and area over parotid gland Sensory - ear and parotid region
Lesser occipital C2 Ascends along posterior border of sternocleidomastoid Skin of scalp posterior to ear Sensory - posterior scalp
Transverse cervical C2-C3 Crosses sternocleidomastoid horizontally Skin of anterior neck Sensory - anterior neck
Supraclavicular C3-C4 Descends to clavicular region Skin over clavicle, shoulder, upper chest Sensory - clavicular and upper chest region
Phrenic C3-C5 Descends through thorax to diaphragm Diaphragm Motor - diaphragm contraction; sensory - central diaphragm, pleura, pericardium

Brachial Plexus (C5-T1)

Nerve Origin Course Distribution Function
Musculocutaneous Lateral cord (C5-C7) Through coracobrachialis to anterior compartment of arm Coracobrachialis, biceps brachii, brachialis; skin of lateral forearm Mixed - motor to anterior arm muscles, sensory to lateral forearm
Median Lateral cord (C6-C7) and Medial cord (C8-T1) Courses with brachial artery through arm, passes through carpal tunnel Most anterior forearm muscles; thenar muscles, lateral lumbricals; skin of lateral palm, thumb, index, middle, lateral half of ring finger Mixed - motor to anterior forearm and thenar muscles, sensory to lateral palm and digits
Ulnar Medial cord (C8-T1) Runs medial to brachial artery, passes posterior to medial epicondyle Flexor carpi ulnaris, medial half of flexor digitorum profundus; most intrinsic hand muscles; skin of medial palm, medial half of ring finger, little finger Mixed - motor to medial forearm and most intrinsic hand muscles, sensory to medial hand
Radial Posterior cord (C5-T1) Courses through spiral groove of humerus Triceps, anconeus, brachioradialis, extensor muscles of forearm; skin of posterior arm, forearm, dorsolateral hand Mixed - motor to posterior arm and forearm, sensory to posterior arm, forearm, dorsolateral hand
Axillary Posterior cord (C5-C6) Passes through quadrangular space Deltoid, teres minor; skin over deltoid Mixed - motor to shoulder muscles, sensory to shoulder region
Suprascapular Upper trunk (C5-C6) Passes through suprascapular notch Supraspinatus, infraspinatus Mixed - motor to rotator cuff muscles, sensory to shoulder joint
Long thoracic C5-C7 directly Descends on lateral thoracic wall Serratus anterior Motor - scapular stabilization

Lumbar Plexus (L1-L4)

Nerve Origin Course Distribution Function
Iliohypogastric L1 Courses through abdominal wall Lower abdominal muscles; skin above pubis and lateral hip Mixed - motor to abdominal muscles, sensory to lower abdomen and lateral hip
Ilioinguinal L1 Accompanies spermatic cord or round ligament Lower abdominal muscles; skin of upper medial thigh, external genitalia Mixed - motor to lower abdominal muscles, sensory to genitalia and medial thigh
Genitofemoral L1-L2 Descends on psoas major Cremaster muscle; skin of anterior scrotum/labia and anterior thigh Mixed - motor to cremaster, sensory to genitalia and anterior thigh
Lateral femoral cutaneous L2-L3 Crosses iliacus, passes under inguinal ligament Skin of lateral thigh Sensory - lateral thigh
Femoral L2-L4 Descends through femoral triangle Quadriceps, sartorius, pectineus; skin of anterior thigh and medial leg Mixed - motor to anterior thigh muscles, sensory to anterior thigh and medial leg
Obturator L2-L4 Passes through obturator foramen Adductor muscles; skin of medial thigh Mixed - motor to adductor muscles, sensory to medial thigh

Sacral Plexus (L4-S4)

Nerve Origin Course Distribution Function
Sciatic L4-S3 Passes through greater sciatic foramen, descends posterior thigh Hamstrings; all leg and foot muscles via its branches; skin of posterior thigh, most of leg and foot Mixed - motor to posterior thigh, all leg and foot muscles, sensory to most of leg and foot
Superior gluteal L4-S1 Passes through greater sciatic foramen Gluteus medius, gluteus minimus, tensor fasciae latae Motor - hip abduction and medial rotation
Inferior gluteal L5-S2 Passes through greater sciatic foramen Gluteus maximus Motor - hip extension and lateral rotation
Pudendal S2-S4 Passes through greater sciatic foramen, reenters through lesser sciatic foramen External anal sphincter, urethral sphincter, perineal muscles; skin of perineum and external genitalia Mixed - motor to perineal muscles and sphincters, sensory to perineum and genitalia

Major Peripheral Nerves of the Upper Limb

Nerve Origin Course Distribution Function
Anterior interosseous Branch of median nerve Descends on interosseous membrane Deep anterior forearm muscles (flexor pollicis longus, lateral flexor digitorum profundus, pronator quadratus) Motor - deep finger and thumb flexion, forearm pronation
Posterior interosseous Branch of radial nerve Courses through supinator, descends on interosseous membrane Deep posterior forearm muscles (extensors of wrist and digits) Motor - wrist and digit extension
Superficial branch of radial Terminal branch of radial nerve Courses under brachioradialis to dorsum of hand Skin of dorsolateral hand and proximal digits Sensory - dorsolateral hand and digits
Digital nerves Terminal branches of median and ulnar nerves Course along sides of digits Skin of digits; small muscles of digits Mixed - sensory to digits, motor to small digital muscles

Major Peripheral Nerves of the Lower Limb

Nerve Origin Course Distribution Function
Common fibular (peroneal) Division of sciatic nerve Courses around fibular neck Lateral and anterior compartment muscles of leg; skin of lateral leg and dorsum of foot Mixed - motor to ankle dorsiflexors and evertors, sensory to lateral leg and dorsal foot
Deep fibular (peroneal) Branch of common fibular nerve Descends in anterior compartment Tibialis anterior, extensors of toes; skin between 1st and 2nd toes Mixed - motor to dorsiflexors, sensory to first web space
Superficial fibular (peroneal) Branch of common fibular nerve Descends in lateral compartment Fibularis longus and brevis; skin of distal lateral leg and dorsum of foot Mixed - motor to evertors, sensory to lateral leg and dorsal foot
Tibial Division of sciatic nerve Descends through popliteal fossa and posterior leg Posterior compartment muscles of leg; skin of posterior leg and sole of foot Mixed - motor to plantar flexors and invertors, sensory to posterior leg and plantar foot
Sural Usually formed by branches of tibial and common fibular nerves Descends lateral leg with small saphenous vein Skin of posterolateral leg and lateral foot Sensory - posterolateral leg and lateral foot
Medial plantar Branch of tibial nerve Courses through plantar foot Abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, first lumbrical; skin of medial sole and medial 3.5 toes Mixed - motor to medial plantar muscles, sensory to medial sole and toes
Lateral plantar Branch of tibial nerve Courses through plantar foot Most intrinsic foot muscles; skin of lateral sole and lateral 1.5 toes Mixed - motor to most intrinsic foot muscles, sensory to lateral sole and toes

Sympathetic Nervous System

Structure Origin Course Distribution Function
Sympathetic trunk Thoracolumbar spinal cord (T1-L2) Paravertebral chain ascending to head and descending to pelvis Head, neck, thorax, abdomen, pelvis, limbs Activates "fight or flight" response - increases heart rate and blood pressure, dilates bronchioles, dilates pupils, increases sweating, decreases digestive activity
Cervical ganglia Superior, middle, inferior ganglia on sympathetic trunk Various pathways via plexuses around arteries Head, neck, upper thorax Pupil dilation, inhibition of salivary glands, increases heart rate
Celiac ganglia Thoracolumbar splanchnic nerves Forms celiac plexus around celiac artery Stomach, liver, gallbladder, pancreas, spleen, kidneys, adrenals, small intestine Decreases digestive secretions and motility, constricts splanchnic vessels
Superior mesenteric ganglia Thoracolumbar splanchnic nerves Forms superior mesenteric plexus Small intestine, proximal large intestine Decreases intestinal secretions and motility
Inferior mesenteric ganglia Lumbar splanchnic nerves Forms inferior mesenteric plexus Distal large intestine, rectum, bladder, reproductive organs Constricts colonic vessels, inhibits defecation, controls ejaculation

Parasympathetic Nervous System

Nerve/Nucleus Origin Course Distribution Function
Edinger-Westphal nucleus Midbrain Via oculomotor nerve Pupillary sphincter, ciliary muscle Pupillary constriction, accommodation for near vision
Superior salivatory nucleus Pons Via facial nerve, chorda tympani Submandibular, sublingual salivary glands Stimulates salivation
Inferior salivatory nucleus Medulla Via glossopharyngeal nerve Parotid salivary gland Stimulates salivation
Dorsal motor nucleus of vagus Medulla Via vagus nerve Heart, lungs, esophagus, stomach, small intestine, proximal large intestine, liver, pancreas Decreases heart rate, increases bronchial secretions, increases digestive secretions and motility
Sacral parasympathetic nuclei Sacral spinal cord (S2-S4) Via pelvic splanchnic nerves Distal large intestine, rectum, bladder, reproductive organs Stimulates defecation, urination, and genital responses